Friday, 4 March 2016

Early March Compost

The new composts that have been on the go for about two or three weeks now have not started to decompose very much yet.  They have changed colour to some extent although there are some things that are still green.  The woody components are starting to become brittle and are much easier to break into smaller pieces.  I chop them up using the shovel. 
Woody compost material slowly changing colour. 
The problem is that I keep on adding new material to the bins.  Having to wait for this to decompose means that the compost is taking more time than usual to break up into smaller pieces.  There is a marked decrease in volume leaving space for more material to be added.  I need to resist the temptation to put more stuff in the bins.  I have used a lot of woody shreddings in all of this new compost to see if it will rot down quickly. 

The change in volume could be a result of two things.  There may be a breakdown of the material into carbon dioxide and this will be lost from the heap as a gas or there may just be consolidation of the material.  Consolidation is more likely to occur when the compost breaks down into smaller pieces allowing it to fall into the voids produced by larger more resistant pieces of compost. 

All the bins have similar material in them.
The bins are being turned regularly but not necessarily every two days.  This may be why they have not begun to decompose very quickly, although this lack of decomposition is more likely to be a result of the cold weather.  Even though this compost is not rotting down very quickly, it is breaking up into smaller pieces fairly rapidly. 

After taking the bins off the compost it leaves a neat pile that can easily be put back into the bins. 
Although it is not decomposing very quickly it is changing colour and breaking up.
The neat "sand castle" like piles fall apart quickly and need a shovel to put them back into the bins. 
Refilled green bin.

This compost consists of woody shreddings; prunings from blackberry and blackcurrant bushes; weeds and kitchen scraps.  There is orange peel in the compost and this will break down very quickly once it starts to decompose.  I have also put quite a bit of cardboard into the bins but this rots down remarkably quickly just leaving the plastic sticky tape that was holding it together and a few plastic labels.  I didn't see any cardboard when turning the composts today. 

There are still some bindweed, horsetail and couch grass in the bins and these are regenerating a little so if I see any rhizomes with buds, I take them out to dry for a week. 

There may be some that stand aghast at the materials used to make this compost but these are the organic materials I have at hand.  And they do rot down.  Admittedly they rot down a lot quicker if they are shredded or broken up.  However, if you take the example of a wooded area, the rain of dead wood that falls from the trees throughout the year would build up to very noticeable levels if there was no decomposition.  It is also said that the soil fertility under temperate woodland is extremely high.  Now why is that?

Only the woody shreddings have been imported into the allotment.  The rest is a recycling of what is already here.  None of this has cost any money at all.  Nutrients that are in the composted material will be retained and not taken off the allotment to be put into green bins or council waste sites.  It will not be burnt so that nutrients are lost due to being changed into gaseous oxides.  Once it has broken down more completely and makes a black or very dark brown compost which can easily be sieved, it will be either used as a mulch or dug into the top soil of the allotment. 

I do import animal manures to put into the top soil but there are resources on the allotment already that I want to use.  These waste products from the allotment itself are the ones that I want to utilise rather than expensive imports.  I cannot, even if I wanted to, justify importing very expensive manures and fertilisers every year. I originally started allotmenteering to see how much food I could produce with as little expense as possible.  I must admit that during the following years I tended to rely more and more on imported nutrients.  However, now I am going to go back to my original idea of growing with the least input from outside the allotment as possible. 

A further reason for making the small ditches alongside the hard surface trackway is that the swale can be filled with stones.  One of the main contributors to the weathering of stones and smaller soil mineral particles are the mychorrhizal fungi.  Saprophytic fungi may also have a role if there is enough organic matter in the soil.  Fungal hyphae grow around mineral particles and stones and slowly decompose them using strong acids secreted from their tips.  These acids include oxalic, malic, citric and carbonic acids.   Nutrients from the stones are dissolved by these acids and pass into the soil solution so that they can be used by both plants and fungi. 

It could be said that this was a very slow process - and it probably is however, where else do the mychorrhizal fungi get their nutrients from?  They may forage for  nutrients dissolved in the soil solution but they would have to compete for these with the rest of the soil population.  The weathering of nutrients from soil particles seems to be a niche which fungi are uniquely adapted to exploit.  As to the small amount of nutrients that may result, plants and fungi need very tiny amounts of these elements.  The fact that they do break them down and that there are enough nutrients in the soil to sustain plant and fungal life, although never enough, means that these nutrients are being replenished and not just being leached away in the ground water. 

There has been some speculation about the presence of glomalin in the soil.  This protein seems to be associated with the cell walls of fungi.  Originally it was thought that fungi secrete this protein but it did not seem to have any benefit.  Associated with the cell wall of the fungi it may be a method of tightly binding the hyphae to soil particles.  It could be a sticky agent that allows fungal hyphae to attach themselves to stones in order to produce a more intimate association in order to dissolve minerals using secreted acids.  This would then explain why glomalin has been so  closely associated with formation of soil aggregates that are water stable.  These soil aggregates are very important in the dynamics of mass water flow and the recycling organic matter. 
Stones sieved out of the growing area top soil and added to the mini ditch. 

So while it can be quite irritating to have excessive large stones littering the growing area, maybe they should not be thrown away but used somewhere that mychorrhizal fungi can reach and weather down to produce nutrients for the rest of the allotment.  What fascinated me was watching gardeners carefully remove stones from their growing areas and taking them away only to replace them with rock dust.  Admittedly, rock dust will weather much more quickly than stone but they are more or less made out of the same thing.   I would suggest that the stone that I have put in the ditches has a greater variety of minerals than those in the bag of rock dust.  Something we have to thank the glaciers of the ice age for. 

Apart from capturing hard surface water run off from the trackway, slowing it down and spreading it out so that it can soak in slowly, maybe the stone filled ditches will increase the total nutrient content of the allotment by using the mychorrhizal fungi planted under the laburnum trees espaliered alongside the path.  These fungi will have unfettered access to the stones in the mini ditches, moreover the nutrients produced will be able to flow down the allotment because of the gentle slope towards the south.


  1. That part about the stones is VERY enlightening. I had no idea that was the case as I had always assumed that weathering alone led to the breakdown of the surface stones.
    Thanks for all the 'science' you discuss. I actually understand some of it. :) Happy Spring.

    1. You are very welcome Barbee. I was hoping that I was not making these blogs too scientific, however I am beginning to question more and more of the accepted truths of gardening. We have gone back to winter again here. It snowed yesterday, but the snowdrops, crocus and daffodils are starting to flower with some force now so I think we will have a good spring. Hope that yours is just as good.

  2. Any nutrients from your stones will be very very small! You are obviously hopeing to live a long time Tony - and so you will with all the exercise you get turning your compost!
    Glad you are returning to the ethics of Eve Balfour and recycling rather than importing. I am sure you will counter my scepticism. Keep up the good work.

    1. Hi Roger,. Every little helps even in the organic gardening sphere if I don't sink under all the effort. :-))